This invention relates generally to the marking of X-ray film during the exposure thereof; more specifically, it relates to a means for conveniently and reliably affixing an X-ray marking device to a cassette that is adapted to hold X-ray film, such that an image of the marking device will be reproduced on the film when it is exposed to radiation.
It is well known in the medical field to mark X-ray film so that the part of a patient's body (e.g., a hand, an arm, etc.) that is "X-rayed" may be clearly identified on the film. Generally, the marking of X-ray film is accomplished by first placing a marking device that is at least partially impermeable to X-rays on the outer face of a suitable cassette, in such a way that the marker overlies a sheet of X-ray film concealed inside the cassette. When the film is exposed to radiation, an image of the marker will be reproduced on the film. Typical identifying characters on the markers are the letters L (for left) and R (for right); another major feature of such markers is a bubble-type level indicator, so that a surgeon, nurse, etc., can later determine whether a particular X-ray was made while the patient was standing erect or lying on a table. Unfortunately, the current methods for affixing a marking device to an X-ray film cassette often prove to be inconvenient and unreliable.
Perhaps the most common method for affixing a marker to a cassette is to use a strip of masking tape or surgical tape to secure the marker to the outer face of the cassette. A frequent problem with this method is that the tape generally loses its adhesive qualities after only a few uses--and the tape can very quickly become ineffective if it picks up dust, is exposed to moisture or liquids, etc. Also, the strip of tape is usually affixed over the marker in such a way that an X-ray technician cannot visually confirm the identifying character of the marker, because the character is often completely concealed underneath the opaque tape. This tends to cause the erroneous marking of X-ray film when a technician switches from, say, a patient's right arm to the left arm--but forgets to also switch markers. As the loaded cassette is inserted into the drawer of an X-ray table, the imminent error in identifying the exposed film is not likely to be caught because the marker is hidden from view.
Another problem experienced by X-ray technicians is that marking devices often are not adapted to be positively and securely affixed to the cassette; some marking devices are susceptible to being dislodged from the cassette while it is being loaded in the drawer of an X-ray table. This is especially a problem when the drawer opening is just barely high enough to allow the cassette to pass through the opening. That is, when the cassette drawer is being closed, a thick-profile marker on top of the cassette face might accidentally contact the upper edge of the drawer opening and be repositioned on--or be completely dragged off of--the cassette face. One other difficulty that X-ray technicians might encounter while attempting to suitably mark X-ray film for the subsequent enlightenment of a doctor is that of precisely locating the perimeter of a sheet of X-ray film concealed inside the cassette. Knowing exactly where the film is located within a cassette is essential to ensure that the marker is positioned within the film boundaries--and to ensure that the marker will be reproduced in its entirety on the subsequently exposed X-ray film. Hence, there has existed a need for a fastening combination which may be used to conveniently and reliably affix a marking device to the outer face of an X-ray cassette--so as to guarantee that the marker's identifying character will be properly reproduced on the sheet of X-ray film when it is exposed.
In the health care industry, it is common to use (Velcro-type fasteners) for a variety of fastening tasks. But insofar as is known, no one has ever used such fasteners for affixing an X-ray marking device to essentially any part of an X-ray cassette face--and yet do so in such a way as to ensure that the marking device will be reliably positioned within the boundaries of a sheet of X-ray film concealed inside the cassette.
Of course, there have been some prior art devices which have at least partially addressed some of the problems specifically related to affixing a marker to an X-ray cassette. Examples of these devices are shown in the following U.S. Pat.: Nos. 4,127,774 to Gillen entitled "X-Ray Marker"; and No. 4,426,723 to Rouse entitled "X-Ray Marker Device." These devices disclose suction cups for affixing a marker to the X-ray cassette. However, in order for the suction cups to have any chance of working effectively, the outer face of the cassette generally must be very smooth and flat. Thus, these devices probably would not be very useful with cassettes having a textured outer surface. And to reliably attach this suction-cup type of fastener to a flat cassette face, the cassette face must be regularly wiped clean so as to remove anything that could interfere with achieving a good seal between the suction cup and the cassette face. Also, marking devices that use suction cups for affixation are inherently so tall that they generally will not clear the top edge of the thin drawer openings in modern X-ray tables.
Other prior art devices employ magnets to affix a marker to the outer face of an X-ray cassette. Exemplary of such devices are those shown in the following U.S. Pat.: Nos. 4,698,836 to Minasian entitled "Means and Techniques Useful in Marking X-Ray Film"; and No. 3,518,428 to J. Ring entitled "Magnetically Attractive Identifying Plates for Attachment to X-Ray Cassettes." However, the magnetic force holding the marker to the cassette face probably would not be sufficient to resist a force acting on the marker in a transverse direction with respect to the cassette face. In other words, if the cassette should be inadvertently bumped while a technician is loading it into an X-ray drawer, the marker might accidentally be moved and reoriented on the cassette face. Another limitation of this type of fastening configuration is that it can only be used to fasten a marker to a steel or similar magnetically susceptible material on the cassette face. Thus, a magnetic marker could not be affixed to a cassette face formed from plastic, aluminum or the like.
There is one other device shown in U.S. Pat. No. 4,194,122 to Mitchell, et al. entitled "Apparatus for the Marking of X-Ray Film" which expressly acknowledges the need to securely fasten a marker to a cassette face. But this type of fastening configuration utilizes elaborate, multi-layered adhesive pads and tabs; and like a strip of masking tape, the adhesive materials have a limited useful life. In fact, Mitchell states (at column 2, lines 46 through 51) "when the adhesive coating on the lower face of the pad becomes dirty or otherwise loses its adhesive qualities with repeated use, the pad is removed. . . . A new pad is then applied to the support sheet." Moreover, the Mitchell fastening combination probably would not be very resistant to moisture or any liquids that might accidentally be splashed on the face of the cassette.
While the above-described devices have been configured for marking X-ray film, it seems that the designers of these prior art devices disregarded the importance of conveniently and reliably marking a cassette so as to positively ensure that the identifying character of the marker will appear on the subsequently exposed X-ray film. Accordingly, there has remained a need for a dependable fastening combination that is configured so as to guarantee that a marking device will remain properly positioned on the outer face of a cassette, in such a way that an image of the marker will be imprinted on the X-ray film when it is exposed. It is an object of this invention to provide such a dependable and convenient fastening combination for securely affixing a marking device to an X-ray cassette.
Another object is to provide a fastening combination that is configured to resist transverse movement of a marker across the cassette face, so as to prevent the marker from being easily dislodged and dragged beyond the periphery of a sheet of film within the cassette.
A further object is to provide a fastening combination that is configured so that a marker may clearly and positively be positioned so as to overlie the sheet of X-ray film.
Still another object is to provide a fastening combination that includes a relatively large sheet of pile-like material which is affixed to the outer face of the cassette in such a way as to define at least a portion of the periphery of a sheet of X-ray film concealed inside the cassette.
One other object is to provide a fastening combination that is reusable and has an essentially indefinite functional life.
These and other objects will no doubt be apparent from a reading of the specification and claims, and from a study of the accompanying drawing illustrating certain facets of the invention.